Yes.

There are some pics of a Mini in here

http://www.songofthepaddle.co.uk/forum/showthread.php?23826-Cars-and-Canoes-a-visual-guide

but also there are a variety of canoes on everything from a nissan micra upwards.

I've had 3 on my Fit...

I will be using Yakima Bow Down Racks on my BMW 3 Sport wagon.  It is a little car.  I purchased Yakima Whispbars the extend past the factory rack, and I am pretty sure I will be able to carry two boats.  I used to just throw my plastic boats in the back of my truck, but my soon to be launched SW sport needs TLC.

I have a 2009 honda fit and have carried three kayaks on it many times-   a shearwater 16, my wife's custom strip boat 16' and a plastic 13'.  

no problems at all.  I have a Thule rack,  also have carried to kayaks and two road bikes at the same time (the bars are a little longer and stick out maybe 3 extra inches on each side.  you only hit your head on it once before you learn to get in and out of the car a little lower.  wife has no problem because she is only 5' tall.

I have seen a lot of people with that familiar small type of car and carry 2 kayaks and had some more equipment stowed up top.

It all depends on the type of bars that you put and use anyway as that would actually determine how things are to hold up on that end of the floor.

But in most cases that you actually see them not working or cause bad effects on your ride stability, you can just always take them out.

I found ot that the Mini has an Aluminum roof and dents easly and can not carry alot of weight. The Clubman has built in rails that are rated for 165 lbs more than enough. Thanks for input 

Phil